Laserfiche WebLink
STAFF REPORT _6_ <br /> PAT MITCHELL AND CALIFORNIA NATURAL PRODUCTS <br /> LATHROP, SAN JOAQUIN COUNTY <br /> within the soil matrix or is released to the atmosphere. Denitrification rates vary substantially <br /> (from 0% to 90% of total nitrogen), depending on several variables,most of which are site- <br /> specific. These variables include those related to soil type or texture; mass of nitrogen per <br /> application per unit area; volume of water per application per unit area; resting or drying time <br /> between applications; and climactic conditions. Therefore, determination of the denitrification <br /> rate for a given discharge can only be made based on a fully supported site-specific model. <br /> The Discharger has stated that a considerable percentage of nitrogen is lost to the atmosphere <br /> through the process of denitrification. Because of the variable denitrification rate that occurs due <br /> to wastewater application rates, ambient temperature, and other factors which may not be <br /> controllable, staff believes requiring agronomic application rates are justified. <br /> Based on long-standing practice, the agronomic nitrogen loading rate for a given crop is based on <br /> the rates presented in the most recent edition of the Western Fertilizer Handbook unless the <br /> Discharger demonstrates that another rate is technically justified. <br /> Staff has taken a conservative approach in requiring the Discharger to apply nitrogen at <br /> agronomic rates. This limit will apply until the Discharger can provide additional site-specific <br /> testing data to support their denitrification assumptions. <br /> Recommendation <br /> Staff recommends that the Board adopt the WDRs as proposed. <br />